Wind indicator

ABSTRACT

Wind indicator apparatus for indicating air flow comprising: a direction pointer, including a vane member, for providing a visible indication of air flow direction; pivoting means including a fixed portion for coupling to a sailing craft and a pivotable portion able to pivot with respect to said fixed portion and with which said direction pointer is entrained for movement therewith; and a counterbalance extending from said pivotable portion of said pivoting means and arranged to move therewith, the mass of the counterbalance being disposed so as to maintain the direction pointer in a substantially level position.

The present invention relates to apparatus for determining andindicating wind direction. In particular, but not exclusively, theinvention relates to an apparent wind indicator for indicting prevailingairflow close to a sailing craft.

It is well known that on many occasions it is advantageous to be able todetermine the direction of airflow in an environment. The skilled personwill understand that airflow will be the result of both wind and airflowcaused by movement of a craft or vehicle. This airflow component willbecome greater as the velocity of movement increases. The resultantairflow is the prevailing airflow. The prevailing airflow causes aneffect equivalent to an apparent wind. This apparent wind will beassociated with a corresponding wind direction as will also beunderstood by those skilled in the own.

Many devices have been disclosed in the prior art for determiningapparent wind direction. In addition to determining the apparent winddirection it is often advantageous to be able to display this directionclearly and visibly so that a human being can simply detect, by lookingat the apparent wind detector, in which direction the apparent wind iscoming from.

Apparent wind detectors are of particular use in the fields of marinecrafts this is because apparent winds can have a substantial effect uponthe movement of these craft through the water. The effect isparticularly pronounced when sailing craft are used. These are marinevessels which include sails. In such craft it is particularly useful forsailors to be able to see in which direction airflow is occurring in aregion around the craft and particularly when sudden direction changesoccur.

Apparent wind indicators are known for use with such sailing craft.However a further problem with such indicators is that as the sailingcraft moves on the surface of the sea it can pitch, roll or yawaccording to the waves or other conditions on the sea. This isparticularly a problem in very windy conditions when the waves on thesea can toss the vessel in many directions. Under these circumstancesthe ability to be able to determine and display current wind directionis very important. However under these conditions an apparent windindicator can be hindered by the fact that the sailing craft is not keptlevel. As a result parts of the wind indicator fixed to the ship tend tomove from a horizontal position, that is horizontal with the horizon, asthe craft itself is tossed. This can make the process of identifying theapparent wind direction difficult for sailors on board such a vessel.

U.S. Pat. No. 4,314,477 discloses a wind direction indicator for a sailboat which can be attached to a sail boat and which ensures that anarrowhead indicator maintains a level position as the ship rolls.However the wind direction indicator does not allow for pitching motionof the vessel. When such motion occurs the arrowhead can be fouled sothat wind direction ascertainment is precluded or else the arrowheadpointer moves from the horizontal position making an angle with thehorizon. This makes reading of the wind direction less accurate and moretime consuming.

It is an aim of embodiments of the present invention to at least partlymitigate the above-referenced problems.

According to a first aspect of the present invention there is providedWind indicator apparatus for indicating air flow comprising: a directionpointer, including a vane member, for providing a visible indication ofair flow direction; pivoting means including a fixed portion forcoupling to a sailing craft and a pivotable portion able to pivot withrespect to said fixed portion and with which said direction pointer isentrained for movement therewith; and a counterbalance extending fromsaid pivotable portion of said pivoting means and arranged to movetherewith, the mass of the counterbalance being disposed so as tomaintain the direction pointer in a substantially level position.

According to a second aspect of the present invention there is providedAn apparent wind indicator, for indicating the direction of air flow,comprising: a support arranged for securing to a mast head of a sailingcraft; pivoting means comprising a ball and cup portion arranged at anend portion of said support; a direction pointer, including a vane meanscoupled to the ball portion of said pivoting means and arranged formovement therewith and to point in the direction of prevailing air flow;and a counterbalance extending downwardly from the ball portion of saidpivoting means whereby said direction indicator remains substantiallyhorizontal whether the craft yaws, pitches or rolls.

Embodiments of the present invention have the advantage that, regardlessof an angle of motion of the sailing craft, the direction pointerremains substantially level with the horizon. This provides a clearlyvisible indicator for sailors of the sailing craft to determine apparentwind direction.

Embodiments of the present invention also have the advantage of beingable to determine wind direction regardless of the angle of attack ofthe sailing craft to the prevailing airflow conditions.

Embodiments of the present invention also provide the advantage ofsimple construction and easy maintenance which reduce costs.

For a better understanding of the present invention reference will nowbe made, by way of example only, to the accompanying drawings in which:

FIG. 1 illustrates a sailing craft;

FIG. 2 illustrates possible degrees of motion of a sailing craft;

FIG. 3 illustrates an apparent wind indicator;

FIG. 4 illustrates an apparent wind indicator fixed to a downwardlypitching sailing craft;

FIG. 5 illustrates an apparent wind indicator fixed to a rolling sailingcraft; and

FIG. 6 illustrates a pivoting ball and socket joint.

In the drawings like reference numerals refer to like parts.

FIG. 1 illustrates a sailing craft 10. It will be understood that theinvention is not limited to use with sailing craft but rather could beused where wind direction indication is required for a body which canitself have many degrees of motion. Preferred embodiments of the presentinvention can be used with yachts, dingys, sail boats, oil tankers,frigates or any other maritime vessels.

The sailing craft 10 is shown on water 11 which may be a lake, sea,ocean or other expanse of water. The effect of the water is that thesailing craft 10 will not necessarily float in a horizontal manner butrather will pitch, yaw and roll as will be described hereinafter. Thesailing craft includes a mast head 12 from which sails can depend. Alsoillustrated in FIG. 1 is the substantially horizontal horizon 13. It isknown that sailors can determine the angle of their craft by comparingit with the substantially horizontal horizon. The sailing craft includesa bow region 14 and stern region 15.

FIG. 2 illustrates possible degrees of motion of a sailing craft. Dottedline 20 illustrates a longitudinal axis through the centre of gravity ofthe craft 10. The craft can roll through an angle γ and around this axisas indicated by arrows 21 & 22. A further degree of motion isillustrated by arrow 23. When the sailing craft moves as shown the craftis defined as pitching. This is indicated by pitching angle α. The thirddegree of motion is a yaw motion illustrated by arrows 24 and angle β.The effects of the sea, tides, waves and wind all conspire to move thecraft on the surface of the water in any one or any combination of thesedegrees of motion.

FIG. 3 illustrates an apparent wind indicator 30 in accordance with anembodiment of the present invention which may be fitted to the head mastor any other suitable part of a sailing craft to enable prevailingairflow on the sailing craft to be determined and indicated. It will beunderstood that such an apparent wind indicator could be fixed to anymoveable body where wind direction was required and where the body wassusceptible to movement which might hinder wind indication. It will alsobe understood that parts of such a wind indicator could be made integralwith a part of such a sailing craft or body.

The device 30 which determines wind direction and indicates thisdirection includes a direction pointer 31 which itself includes a vane32, shaft 33 and point 34. The vane member 32 comprises a surface whichis caught by airflow and which turns the direction pointer into the windabout a pivot point. The shaft portion 33 is connected at one end to thevane 32 and at its other end to the point 34. It will be understood thatthe vane, shaft and point could be made integrally from any suitablematerial such as moulded plastic or aluminium. The direction pointerincludes a balancing weight 35 which comprises a relatively dense metalcollar which slips along the shaft 33 and which may be secured by a grubscrew 36 on the shaft 33 at a location selected so as to achieve anoptimum levelness for the direction pointer when fitted to a sailingcraft. It will be understood that the balancing weight 35 could besecured to the shaft 33 in any suitable manner for example by a tightfriction fit, by having a portion of the shaft 33 threaded so that theweight can be screwed up and down the shaft, or by any other suitablemeans. Also the balancing weight may be made of any suitably heavymaterial.

A portion of the shaft 37 extends downwardly at a region of the shaft33. This downward extension forms a housing for a rod 38 (which isillustrated by dotted lines). The rod 38 connects the direction pointer31 to a ball bearing portion 39 of a ball and cup joint 40. The ball andcup joint 40 also includes a cup portion 41. The ball 39 is arranged soas to be able to run smoothly within the cup 41. This is either achievedby having a very close fit for the ball in the cup or by providing aball bearing race on the inside of the cup 41; or any other suitablemethod. The cup 41 may take the form of a ring having an inner peripheryof a size and shape which matches the outer circumference of the ball39.

The cup 41 of the ball and cup joint 40 is connected to a forwardlyextending portion 42 of a support 43. This support 43 may be attached toa mast head 12 of a sailing craft by securing means 44. It will beunderstood that any suitable securing means could be used for securingthe support 43 to a mast head. Alternatively the support 43 andextending portion 44 could be made integrally with a portion of masthead. It will also be understood that the support 43 and securing meanscould be made of any particular configuration to enable the apparentwind indicator to be fixed to any other object.

The apparent wind indicator 30 also includes a counterbalance 45 whichincludes a rod portion 46 and spherical mass 47. The rod portion 46 actsas a support for the weight 47. It will be understood that thecounterbalance may take any form which produces a suitable centre ofgravity below the direction pointer 31. It is particularly advantageousfor the counterbalance to act as a pendulum.

In this way the direction pointer 31 is connected via housing 37 and rod38 to an upper pole region of the ball 39 whilst the counterbalance 45extends via the support 46 and rod 38 to a lower pole region of the ball39. The rod 38 extends from the housing 37 through the ball 39 and intothe support 46 for the mass 47. It will be understood that the presentinvention is not limited to the connection of these elements in thismanner. Rather any alternative such as integral manufacture wouldsuffice so long as the direction pointer 31, ball 39 and counterbalance45 move as an integral unit and may move freely within a fixed portionwhich may be fixed relative to a sailing craft or other object.

FIG. 4 illustrates how the apparent wind indicator 30 maintains asubstantially level position when attached to a mast head 12 of asailing craft which pitches through an angle α. As the sailing craftpitches through this angle the support 43 pitches a corresponding angle.This moves support portions 43 and 42 and the cup 41 of the ball and cupjoint 40. However as the support moves, the ball 39 slips within the cup41 due to the counterbalance 45 which, due to the force of gravity,maintains the rod 38 in a substantially vertical position. The directionpointer 31 which is fixed substantially perpendicular to the axisrunning through the housing 37, ball 39 and support 46 for thecounterbalance 45, is thus kept substantially horizontal. It will beunderstood that the possible angles through which a sailing craft maysafely pass without sinking are limited. The angle of the forwardlyextending section of the support 42 and dimensions of the vane 32 areselected to be able to cope with all such possible angles withoutbecoming entangled. For example if greater angles are to be expected theportion of the vane 32 shown in FIG. 4 with dashed lines, may beremoved. Alternatively a further configuration of vane 32 may be made aswill be understood by those skilled in the art. It would also bepossible to extend the housing portion 37 connecting the ball 39 to thedirection pointer 31 so as to give more clearance from the support 42and 43.

FIG. 5 illustrates how the apparent wind indicator 30 operates when thesailing craft rolls. The apparent wind indicator is secured to mast head12 via securing means 44. The cup portion of the pivoting means 40 isfixed to the support 43 and thus is fixed in position relative to themast head. As the craft rolls through angle γ the fixed cup portionlikewise moves. However the ball portion 39 of the pivoting means rollswithin its joint due to the forces exerted by the counterbalance 47.This force is due to the gravitational effects on the mass of thespherical ball 47. It will be understood that any shape mass wouldsuffice. Since the ball can roll and rock and twist within the confinesof the cup, the direction pointer is maintained in a substantiallyhorizontal position. A sailor on the sailing craft 10 would thus be ableto easily check the apparent wind direction even though the vessel wastilting quite substantially.

FIG. 6 illustrates the pivoting ball and socket joint of the windindicator apparatus in more detail. The ball and socket joint comprisesa first fixed joint part 41 which forms a joint cup, and comprises asecond joint part 39 which has a spherical surface 60 which is mountedin the joint cup such that it can slide. The sliding motion results fromthe close contoured fit of the inside surface 61 of the cup portion. Itwill be understood that as one of many alternatives a race could beprovided on the inner surface of the cup portion 41 so as to confine theball but allow it to slide substantially freely. The ball 39 is arrangedcentred at the centre of curvature of the joint cup.

The fixed portion 41 can form an end portion of the forwardly extendingsupport 42 or can be fixed to the forwardly extending portion as isknown in the art. The dotted lines 62 illustrate that the cup portionsurrounds the ball 39. It will be understood that the ball 39 can thuspivot (or slide) within the cup portion. The pivoting can be a rockingmotion or a turning motion about the imaginary longitudinal axis throughthe centre of the mast 47 along rod 46 through the centre of mass of theball 39 and through into housing 37. The direction pointer can thus turnaround this axis. Alternatively the ball can rotate within the cupportion to accommodate forward and backward and side to side motion.

It will be understood that as the sailing craft yaws the mast head orother portion to which the apparent wind indicator is affixed will movetherewith. However the counterbalance will operate to maintain thepointer in a substantially level position whilst the fixed portion ofthe pivoting means will move relative thereto due to its fixedrelationship with the mast head. The direction pointer can still turninto the wind, by rotating about the longitudinal axis of the rod 38.This is because the ball 39 can rotate within the fixed housing 41.

It will be noted that whilst the above describes preferred embodimentsof the invention, variations and modifications may be made withoutdeparting from the scope of the present invention.

1. Wind indicator apparatus for indicating air flow comprising: adirection pointer, including a vane member, for providing a visibleindication of air flow direction; pivoting means including a fixedportion for coupling to a sailing craft and a pivotable portion able topivot with respect to said fixed portion and with which said directionpointer is entrained for movement therewith; and a counterbalanceextending from said pivotable portion of said pivoting means andarranged to move therewith, the mass of the counterbalance beingdisposed so as to maintain the direction pointer in a substantiallylevel position.
 2. The apparatus as claimed in claim 1 wherein saidpivoting means comprises a ball and cup joint in which said fixedportion comprises a cup member and said pivotable portion comprises aball member arranged to roll within the cup member.
 3. The apparatus asclaimed in claim 2 wherein the direction pointer is disposed at an upperpole portion of the ball member and the counter balance extends from alower pole portion of the ball member, a line between the three pointsof the upper pole, centre of the ball member and lower pole defining anaxis of rotation about which the direction pointer can rotate.
 4. Theapparatus as claimed in any one of claims 1 to 3 wherein said cup membercomprises a ring having an internal profile matched to the shape of theouter circumference of the ball member.
 5. The apparatus as claimed inany one of claims 1 to 3 wherein said cup member comprises a ring andincludes a further race member comprising a plurality of ball bearingsarranged around the periphery of said ring so as to entrap the ballmember and yet allow the ball member to roll within the cup member. 6.The apparatus as claimed in any preceding claim further comprising: asupport arranged for securing to said sailing craft, said supportextending from the fixed portion of said pivoting means; whereby whensaid support is secured to the sailing craft, the fixed portion of thepivotable means is fixed in position relative to the sailing craft. 7.The apparatus as claimed in claim 6 wherein said support comprises aforwardly extending bracket portion connected to said fixed portion ofthe pivoting means.
 8. The apparatus as claimed in any one of claims 1to 7 wherein said direction pointer comprises a shaft member having thevane member disposed at a first end thereof and a head member disposedat the further end of the shaft member, said head member providing avisible cue for determining air flow direction.
 9. The apparatus asclaimed in claim 8 wherein said shaft member further comprises abalancing weight which is moveable along the length of at least aportion of the shaft, and which is securable at a selected location tothereby finely adjust the levelness of said direction pointer whenmounted to the sailing craft.
 10. The apparatus as claimed in anypreceding claim wherein said counterbalance comprises: a rod portionextending away from a lower portion of the pivotable portion of thepivoting means; and a spherical mass disposed at a region of said rodportion distil from said pivoting means.
 11. The apparatus as claimed inany preceding claim whereby said direction pointer remains substantiallylevel whether the sailing craft yaws, pitches and/or rolls.
 12. Theapparatus as claimed in any preceding claim wherein said apparatuscomprises an apparent wind indicator for determining and indicating thedirection of prevailing air flow in a region proximate to said windindicator.
 13. An apparent wind indicator, for indicating the directionof air flow, comprising: a support arranged for securing to a mast headof a sailing craft; pivoting means comprising a ball and cup portionarranged at an end portion of said support; a direction pointer,including a vane means coupled to the ball portion of said pivotingmeans and arranged for movement therewith and to point in the directionof prevailing air flow; and a counterbalance extending downwardly fromthe ball portion of said pivoting means whereby said direction indicatorremains substantially horizontal whether the craft yaws, pitches orrolls.